Iron removal apparatus



Patented pr. 22, 1941 -UNITED STATES PATENT OFFICE 2,239,612 IaoN aEMovAL APPARATUS v Joseph P. Lawlor, Ames, Iowa Application .inne 1a, 1940, serial No. 340,383

(ci. 21o- 26) 8 Claims.

My invention relates to means ,for the removal of iron from well water supplies;

Many well waters contain ironin objectionable quantities. Various methods have been devised for the removal of the iron. The general practice-and the same is followed here-is to. oxidize the iron in the waterchan ging,it from a soluble to an insoluble state, then passing the` -water through an ordinary sand filter retaining the insoluble iron precipitate on -the filter sand. Another method commonlyused is to pass the water through a highly oxidized mineral causing oxidation and precipitation at the same time. The third method of removal-is by base exchange. The second and third reduire the use of chemicals resulting in considerable care and attention. The teaching herein prescribed is along the lines of thevflrsit, method, namely, oxidation by aeration, 'then-mtqrnfvlth standard fllters..` j' l,

Heretofore, however, this practice -has been limited in its possibilities owing-alghe fact. that the lter must be back-washed.l occasionally by reversing'l the flow of water through the filter, thereby floating out the residue collected on the filter sand. This back-wash requires a'hfghflow rate and it has been expensive to build a' u nit with storage that would permit satisfactory back-wash flow rates.

Another objection to this method as heretofore practiced 'lies in the fact that the lter itself had to be sufficiently large to accomodate the capacity of the well pump. For example, if the well pump delivered ten gallons per minute, the filter itself would have to be suiiiclently large to efficiently filter ten gallons per minute. The result was that the cost of the plant for domestic and industrial use was out of proportion and too expensive to be considered practical by the majority of households and small industries using water high in iron.

The third objection to the old conventional type has been the complication of valves and piping system necessary for operation and backwash. Y

My invention, therefore, has for its object the overcoming of all of the above mentioned objections, enabling the use of a smaller filter than heretofore through the utilization of storage ,space on both the inlet and outlet sides of the lter, and avoiding the necessity for-using. additional air equipment for the proper back-wash of the filter.

Other objects will in part' be obvious and in part be pointed out hereinafter. l

To the attainment of the aforesaid objects and ends the invention still further resides in the novel details of construction, combination and arrangement of parts, all of which will be nrst fully described in the following detailed descrip- 60 tion, and then be particularly pointed out in the appendedV claims, reference being had to the accompany drawing, in which the figure is a diagrammatic view of an iron removal `plantaccording to my invention.

In the drawing', I is the usual power-driven well pump having means 2 to supply aix' to the water as it leaves the pump to fow through a pipe 3 into a pneumatic pressure tank 4.for storage of raw water, and maintaining the necessary pressure for service lines. n

Under the practice heretofore employed the pipe i connects to the the bottom of tank 4, but when my invention is used the pipe 3 is connected to .tank 4 near its top so that the water will fall through the air in thel tank so' as to induce oxidation of the ferrous iron in order to change it from a soluble to an insoluble state. Y

The tank 4 has an air space in the top part and is provided with the usual pressure gauge-l and with a neat-operated air release valve 5 of conventional form.

A pipe I is connected to the tank 4 near its bottom and conveys the water from that tank via a shut-off valve 8 and cross-pipe 9 to the filter Il where it 'delivers into the top of the filter. The pipe 9 has a T II to which a waste pipe I3, having a shut-'off valve I2, is connected, the waste pipe I3 discharging into a suitable drain I4.

All of the aforementioned articles (I to I4) are in accordance with standard practice for small pneumatic pressure systems, except that I have changed the discharge line 3 from the pump to deliverthe water into the tank 4 at the top .its bottom and has a back-check valve I9 (B. C.

V.) adjacent the tank and one or more faucets 2. at its delivery point or points.

The tank I6, like the tank 4,- has an air space at the top. These air spaces (of tanks 4 and Ii) are connected by, and normally communicate through, an air-pressure-equalizing pipe 2|, there vbeing a shut-olf valve 22 in the line preferably located adjacent tank is). 'rank it is'aiso provided with a oat-operated air 'release valve I1 similar to the valve 5, the valves 5 and` I1 being of any approved construction.

Normally valve 22 is closed, valve l is open, and valve I2 is closed. When faucet 20 is opened water starts movement through pipe Il from two sources, namely, tank I6 and tank 4. It is obvious that when faucet 2B is closed for a period of time the pressures 1n tanks 4 and I6 become balanced. Consequently when faucet 20 is opened, tanks 4 and IB start to feed into pipe I8, repression tank IB feeding direct and tank 4 feeding through the filter I0.

Assume that faucet 2l is opened so as to deliver ten gallons per minute. 'I'his will not result in a ten-gallon-per-minute rate of travel through filter III because of the available storage in repression tank I6. The reduced pressure will, however, start a flow through filter III at the rate of a little less than half the rate at which water is drawn. In other words, the rate 4of ow through the filter would be reduced from ten gallons per minute down to four or five gallons per minute. After faucet 20 is closed water from tank 4 will continue to travel in to repression tank I6 via the filter I0. For example, assume that faucet 20 is opened for one minute and then closed, lter III would start operation as soon as faucet 20 is opened. After faucet 20 is closed the water continues to flow from tank 4 to repression tank IG, through filter I0, for a considerable period of time, or until .the pressure is again equalized in tank 4 and repression tank I6. During the above operation of opening and closing faucet 20, pump I may or may not be operating; that is immaterial. Owing to the fact that the filter is functioning when service valves or faucets areclosed it is obvious that filter III can be much smaller than would be necessary without the use of repression tank I8. This is an improvement; the smaller the filter necessary, the less expensive the installation.

In due time a heavy iron precipitate is collected on top of filter sand and must be removed. This is done by back-washing the filter sand. By back-wash is meant the reversing of the flow of water in filter I so as to travel upward, lifting on .the precipitated iron and carrying it to waste. 'I'he back-washing of this plant is accomplished in the following simple manner.

Close valve 8. Open valve I2. Open valve 22. The filtered water stored in tank I6 then travels back through pipe I5, up through filter tank I0, out pipe 9, through valve I2 and pipe I3 to waste. 'I'he air stored in tank 4 contributes to the pressure in tank I6 when valve 22 is opened. The air pressure is sufficient to force water from tank I6 up through filter III. By the time the water in tank I6 has been exhausted the filter is sumciently clean to put back into operation.

Putting the unit back into operation then merely requires the following: Close valve 2 2. Close valve I2. Open valve 8. By the time this back-wash operation is completed pressure will have dropped in tank 4 sufficient to start pump I. As the water and air pressure builds up in tank 4, approximately one-half of the water pumped moves slowly through filter I0 into repression tank I6. If pump I is delivering ten gallons per minute, filter I0 .is operating at approximately i five gallons per minute as half oi'. the water water through the filter is one of the new features ing operation is performed about twice a week and requires less than two minutes of time. Appiicant knows of no other system that requires less time and attention. Its only operating expense is the extra water that is pumped and used for back-washing, which is a very small quantity. This system is highly economical and sImple-so inexpensive, in fact, that it can be easily adapted for household use. Although this plant is now designed and being built for domestic use on farms and other homes having their own well water supply, it could also be used in connection with city service lines by eliminating the well pump and substituting therefor city waterand retaining an air supply pump. A simple and inexpensive iron removal plant for household use is found vhere. It is accomplished by creating a slow rate of fiow through the filter, thereby making it possible to use a smaller filter. It is further accomplished by providing means for back-washing the filter adequately with clean filtered water that is passed up through the filter sand by means of air storage already existing in both tanks, said air being necessary otherwise to maintain a pressure on the service lines during normal operation. It is made less expensive by the elimination of a number of valves that are ordinarily used. It is less expensive than other types where chemical treatment is required because in this plant no chemicals whatsoever are necessary for the removal of iron under ordinary circumstances.

I have herein described and shown in the accompanying drawing, the preferred embodiment of my invention. I wish it understood, however, that modifications of the same may be made Without departing from the spirit of the invention and within the scope of the appended claims.

From the foregoing, taken in connection with the accompanying drawing, it is thought the construction, operation and advantages of my in-` vention will be clear to those skilled in the art.

Wha't I claim is:

l. In an iron removal system, a raw water storage tank having a water space and having a compressed air space above the water level in the tank, means for admitting water and air into said tank, a repression tank having a water space and also having a compressed air space above the water level in that tank, a water service line connected to the water space of said repression tank and having a back check valve, a lter, a pipe for conveying water from the water space of .said raw water tank into the top of the filter, a pipe for conveying the filtered water from the filter into the water space of the repression tank, a back-Wash line connected to the pipe which conveys the Water from the raw water tank to the filter and having a shut-off valve, there being another shut-off valve in the pipe between the raw water tank and the place of connection therewith of said back-wash line, an air pressure equalizing line connecting the air space ofthe raw water tank with the air space of the repression tank, and a shut-oi valve in said air pressure equalizing line.

2. In a system of the class described, the combination, comprising a source of Water and air under pressure, a compressed air raw-water tank having an air space above the water, a pipe connecting said source with said air space to deliver the water and air through the air in said air space, a compressed air repression tank having a water space and having an air space above the water, a filter operatively connected between said tanks through which water from the raw water line.

acacia tank is filtered and passed into the repression tank, a shut-oli valve in the connection between the raw water tank and the filter, a back-wash line connected with the water inlet end of the filter, a shut-of! valve in said back-wash line, a service'pipe connected to the water space oi' said repression tank, and an air pressure lequalizing line with shut-ofi valve for connecting the air spaces of said tanks together.

3. In a water system, two pneumatic pressure tanks, each having an air spaceat the top, means for delivering air and water into the first of saidv tanks, a service pipe line forl conveying water from the second of said tanks, a filter having an intake end, a pipe for conveying water from the first tank` to the filter, a shut-oii'valve in said pipe, a pipe for conveying filtered water from the filter to the second tank, a back-wash line connected with the intake end of the filter, a shut-of! valve in said back-washsline, and means for equalizing the air pressure in said tanks when the valve between the nrst tank and the filter is closed and the valve in the back-wash waste line is opened, the last-named means comprising an air pressure equalizing line connecting the air spaces of said tanks together. and a normally closed shut-ofi' valve in said air pressure equalizing line.

4. In an iron removal system, a raw water storage tank having a compressed air space above the water level in the tank, a repression tank having a water space and also having a compressed air space above the water level in that tank, a water service line connected to the water space of said repression tank, a back check valve in said water service line, a water supply pipe for delivering water and air under pressure into the air space of said raw water tank, a filter, a pipe for conveying water from the water space of said raw water tank into the filter, a pipe for conveying the filtered water from the filter into the water space of the repression tank, a back-wash line connected to the pipe which conveys the water from the raw water tank to the filter, a shut-H valve in said back-wash line, another shut-of! valve in the pipe between the raw water tank and the piace of connection therewith of said back-wash lines, an air pressure equalizing line connecting the air space of the raw water tank with the air space of the repression tank, and a shut-off valve in said air pressure equalizing 5. In a system of the class described, the combination, comprising a source of water and air under pressure, a compressed air raw-water tank having an airspace above the water, a pipe con necting said source with said raw-water tank, a compressed air repression tank having an air space above the water, a filter operatively connected between said tanks through which water from the raw-water tank is filtered and passed into the repression tank, a shut-oi! valve in the connection between the raw-water tank and the filter, a back-wasn line connected with the water inlet end of the filter, a shut-off valve in said back-wash line, a service pipe connected to the water space of said repression tank, and an air tanks each having an air space at the top, means for delivering water and air under'pressure into the first tank, a service line conveying water' from the second tank, a filter having an inlet side and an outlet side, means including a shutoi! valve for conducting the water from the first tank to the inlet side of the filter, means for conveying the water from the outlet side of the filter into the second tank, means for back-washing the filter, the last named means including a back-wash waste line communicating with the inlet side of the filter, a shut-ofi valve controlling flow through said back wash waste line, and means effecting communication between the air spaces of the two tanks whereby air may iiow from the flrst tank to the second tank and replace the water flowing out of the second tank Awhile the back-washing takes place.

7. In a closed system of water purification. a raw water storage tank and a repression tank each having 'a water space and an air cushion space above the water in the respective tanks, a filter having an inlet side connected to said raw water storage tank and having an outlet side connected to said repression tank, a service pipe line connected with said repression tank, means for forcing water and air into said raw water storage tank above the water level therein and establishing in said raw water tank a sufilcient pressure to force water through said filter and 'into said repression tank against the air cushion therein and store up a supply of water in each of said tanks. means for closing ofi' the flow of water from the raw water tank to the filter and means including an air line connecting the air spaces ofthe two tanks together and including a normally closed back-wash outlet from the filter for effecting a back wash of the filter by the water in the repression tank after having first closed off the flow from the raw water tank to the filter and having opened said back wash outlet.

8. In a closed system of water purification, a raw water storage tank and a repression tank veach having a water space and an air cushion space above the water in the respective tanks, a filter having an inlet side operatively connected to said raw water storage tank and having an outlet side operatively connected to said repression tank, a service pipe-line connected to the lower part of said repression tank, means for delivering water and air under pressure into said raw water storage tank and establishing in said raw water storage tank a sufiicient pressure to force water through said filter and into said repression tank against the air cushion therein and also to store up water in each oi' said tanks, an air line connection from the air space of the raw water storage tank to the air space of the repression tank, means for controlling the passage oi' air through said air line, and a normally closed back wash outlet for the filter. al1 being arranged whereby under normal operation of the apparatus when water is being withdrawn through said service pipe-line the rate of iiow of water from the raw water tank through the filter into the repression tank will be less than the outflow from the repression tank, regardless of the rate at which water is being delivered into the raw watar tank or withdrawn from the repression tank.

JOSEPH P. LAWLOR. 

